Meta-analyses compiling the initial evidence, mainly based on retrospective studies involving hospitalized patients in China, highlighted the association of disease severity and mortality with lymphopenia, thrombocytopenia, elevated levels of C-reactive protein (CRP), procalcitonin (PCT), lactate dehydrogenase (LDH), D-dimer, ferritin, interleukin 6 (IL6), E-selectin, vascular cell adhesion molecule 1 (VCAM1), and Angiopoietin 2 (Angpt2), among others (4–8). This evidence concerns the gene IL6 and lymphopenia.